The specific aim of the proposed research is to explore the meaning of the electrodermal responder/ nonresponder distinction found among schizophrenics and those at risk for schizophrenia, specifically the implication that distinction has for differences in attentional dysfunctions. The existence of subgroups of schizophrenics who fail to show normal orienting responses (ORs), usually as indexed by the skin conductance response, is one of the most reliable autonomic nervous system abnormalities associated with schizophrenia. Since the OR is thought to reflect the allocation of attentional resources to the cognitive processing of stimuli, it reflects one of the most basic aspects of information processing. Because attentional theories of schizophrenia have long been entertained, abnormalities in the OR in this disorder and those at risk for it are inherently of interest. We will identify groups of electrodermal hyperactivated responders and hypoactivated nonresponders from among an existing well-diagnosed population of young, recent, onset schizophrenics and from among a large population of college students identified as at-risk for schizophrenia by their abnormal responses to standardized questionnaires (the Chapman Anhedonia, Perceptual Abberation, and Magical Ideation scales). All subjects will be presented with an orienting take in which certain stimuli are to be attended (OS+) and others are to be ignored (OS-). Allocation of both automatic (preattentive) and controlled information processing capacity of OS+ and OS-will be assessed through the use of two techniques, a probe reaction time stimulus technique and a startle blink stimulus technique. Nonresponder schizophrenics and at-risk subjects are predicted to show reduced ability to allocate processing capacity to the OS+, while responders are predicted to show difficulty in inhibiting allocation of attention to the OS-.